Development of cellulose nanocrystal-stabilized Pickering emulsions of massoia and nutmeg essential oils for the control of Aedes albopictus

We investigated the larvicidal potential of 10 plant essential oils (EOs) against the Asian tiger mosquito Aedes albopictus. Among the EOs, larvicidal activity against Ae. albopictus was strongest in those derived from massoia (Massoia aromatica) and nutmeg (Myristica fragrans). Larvicidal activities of massoia and nutmeg EOs against Ae. albopictus were 95.0% and 85.0% at 50 μg/mL, respectively. A total of 4 and 14 compounds were identified from massoia and nutmeg, respectively, and two massoia lactones, C10 and C12, were isolated from massoia EO. Among the identified compounds, benzyl salicylate, terpinolene, C12 massoia lactone, sabinene, benzyl benzoate, methyl eugenol, and C10 massoia lactone exhibited the strong larvicidal activity. Cellulose nanocrystal (CNC)-stabilized Pickering emulsions of massoia and nutmeg EOs were developed to overcome the insolubility of EOs in water. CNC/massoia and CNC/nutmeg emulsions were stable for at least 10 days, and larvicidal activities of CNC/massoia PE and CNC/nutmeg were higher than those of crude massoia and nutmeg EOs. This study presents a CNC-stabilized PE, a suitable formulation for EOs, as a potential larvicide against Ae. albopictus.